County profile · official public datasets

Monmouth County, NJ

505 public highway bridges tracked in the FHWA National Bridge Inventory: 32.9% rated Good, 58.2% Fair, 8.9% Poor.

505
Public bridges: 32.9%
Good condition: 8.9%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Monmouth County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

16th
of 21 on Poor share: 8.9%
Poor-condition share: 505
public highway bridges: 1971
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Monmouth County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Monmouth County ranks #16 of 21 New Jersey counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.9%). Monmouth County, New Jersey contains 505 public highway bridges. Roughly 32.9% are rated “Good,” 58.2% “Fair,” and 8.9% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

Total bridges

505

Public highway bridges in Monmouth County

Good condition

32.9%

166 of 505 rated 7-9

Fair condition

58.2%

294 of 505 rated 5-6

Poor condition

8.9%

45 of 505 rated 4 or below

In-state Poor-share rank

#16 of 21

Among New Jersey counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 505 NBI-tracked bridges by lowest applicable component rating.

Good

32.9% (166)

Fair

58.2% (294)

Poor

8.9% (45)

Monmouth County's Poor-condition bridges carry 416,947 vehicle crossings a day

That is 4.5% of the county's reported daily bridge traffic on 8.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 9,265 crossings a day against 19,000 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 505 of 505 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

58% of Monmouth County's bridges have passed the 50-year mark

293 of the 505 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 32.9% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 8.3% of the county's Poor-condition bridge traffic

OLD ROAD (NJ 33) over MILLSTONE RIVER, built 1915, carries 34,650 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 45-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 416,947 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

3
1900s

14
1910s

3
1920s

19
1930s

25
1940s

34
1950s

66
1960s

47
1970s

116
1980s

49
1990s

35
2000s

51
2010s

29
2020s

14

What this shows Construction peaked in the 1970s, when 116 of the county's bridges still in the inventory were built, which is 23% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1971, 5 years newer than the New Jersey average of 1966.

How Monmouth County compares with New Jersey's closest counties by inventory size

The 5 New Jersey counties nearest Monmouth County in number of bridges, with their condition splits. Its 8.9% Poor share is the 5th-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1968 is in line with the group.

Showing the 5 closest of 20 New Jersey counties eligible for comparison.

Bridge inventory size and condition shares for Monmouth County and the 5 New Jersey counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Bergen County	577	19.1%	76.1%	4.9%	1964
Middlesex County	563	23.4%	72.1%	4.4%	1972
Morris County	508	19.7%	74.4%	5.9%	1964
Essex County	505	16.2%	81%	2.8%	1963
Monmouth County (this page)	505	32.9%	58.2%	8.9%	1971
Mercer County	414	40.3%	50.5%	9.2%	1975

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Monmouth County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Monmouth County, both outside New Jersey so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NJ (505 bridges here).

Linn County, IA · 506 bridges
Saunders County, NE · 506 bridges
Garfield County, OK · 504 bridges
Oakland County, MI · 508 bridges

Similar average build year

Nearest mean year-built outside NJ (1971 here).

Wayne County, MI · avg 1971 · 1,026 bridges
Baltimore County, MD · avg 1971 · 783 bridges
Washington County, PA · avg 1971 · 655 bridges
Linn County, OR · avg 1971 · 566 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 505 Good 166 Fair 294 Poor 45

Fair-condition bridges (294)

Sort:

Monmouth County Bridge Snapshot

Condition distribution

Monmouth County's Poor-condition bridges carry 416,947 vehicle crossings a day

58% of Monmouth County's bridges have passed the 50-year mark

One structure carries 8.3% of the county's Poor-condition bridge traffic

How Monmouth County compares with New Jersey's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (294)

MATAWAN AVENUE

CR 33 (FLORENCE AV

E. ALDRICH ROAD

HALLS MILL RD

NJ RT 33

CR 6-WEST FRONT ST

WEST FRONT STREET

NJ RT 138 EB

NJ 18 SOUTHBOUND

NJ RT 138 EB

RT NJ 33 FRWY WB

NJ 33 EB

CR524 (ALLAIRE RD)

NJ Route 18 N.B.

DEAL RD

I-195 EB

I-195 WESTBOUND

GSP NBO

DUTCH LANE ROAD

CR 3

LAURELWOOD DR

NJ 18 SB.

RT 138 EB

CR 29 ATLANTIC AVE

NJ 18 NB

YELLOW MT HOUSE RD

CR 537 & RAMPS

CR 520 (E.MAIN ST)

DAVIS STA-IMLTN.RD

COUNTY RT 527 ALT

NJ 18 NB

OCEAN AVENUE

COUNTY ROUTE 18I

NJ 79

JUMPING BROOK ROAD

SHARON STATION RD

CR29 ATLANTIC AVE.

WILLOW BROOK ROAD

NJ 18 FREEWAY SB

NJ 79

HOMINY HILL ROAD

ARNYSTN-HRNRSTN RD

NJ 35

NJ 18

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